Mocellin Ramon, Walterfang Mark, Velakoulis Dennis
Neuropsychiatry Unit, The Royal Melbourne Hospital, Parkville, Victoria, Australia.
CNS Drugs. 2007;21(10):799-811. doi: 10.2165/00023210-200721100-00002.
Hashimoto's encephalopathy is a term used to describe an encephalopathy of presumed autoimmune origin characterised by high titres of antithyroid peroxidase antibodies. In a similar fashion to autoimmune thyroid disease, Hashimoto's encephalopathy is more common in women than in men. It has been reported in paediatric, adult and elderly populations throughout the world. The clinical presentation may involve a relapsing and remitting course and include seizures, stroke-like episodes, cognitive decline, neuropsychiatric symptoms and myoclonus. Thyroid function is usually clinically and biochemically normal.Hashimoto's encephalopathy appears to be a rare disorder, but, as it is responsive to treatment with corticosteroids, it must be considered in cases of 'investigation negative encephalopathies'. Diagnosis is made in the first instance by excluding other toxic, metabolic and infectious causes of encephalopathy with neuroimaging and CSF examination. Neuroimaging findings are often not helpful in clarifying the diagnosis. Common differential diagnoses when these conditions are excluded are Creutzfeldt-Jakob disease, rapidly progressive dementias, and paraneoplastic and nonparaneoplastic limbic encephalitis. In the context of the typical clinical picture, high titres of antithyroid antibodies, in particular antithyroid peroxidase antibodies, are diagnostic. These antibodies, however, can be detected in elevated titres in the healthy general population. Treatment with corticosteroids is almost always successful, although relapse may occur if this treatment is ceased abruptly. Other forms of immunomodulation, such as intravenous immune-globulin and plasma exchange, may also be effective. Despite the link to autoimmune thyroid disease, the aetiology of Hashimoto's encephalopathy is unknown. It is likely that antithyroid antibodies are not pathogenic, but titres can be a marker of treatment response. Pathological findings can suggest an inflammatory process, but features of a severe vasculitis are often absent. The links between the clinical pictures, thyroid disease, auto-antibody pattern and brain pathology await further clarification through research. It may be that Hashimoto's encephalopathy will be subsumed into a group of nonvasculitic autoimmune inflammatory meningoencephalopathies. This group may include disorders such as limbic encephalitis associated with voltage-gated potassium channel antibodies. Some authors have suggested abandoning any link to Hashimoto and renaming the condition 'steroid responsive encephalopathy associated with autoimmune thyroiditis' to better reflect current, if limited, understanding of this condition.
桥本脑病是一个用于描述一种推测为自身免疫性起源的脑病的术语，其特征为抗甲状腺过氧化物酶抗体滴度升高。与自身免疫性甲状腺疾病类似，桥本脑病在女性中比在男性中更常见。全世界的儿童、成人和老年人群中均有病例报道。临床表现可能呈复发缓解型，包括癫痫发作、类中风发作、认知功能下降、神经精神症状和肌阵挛。甲状腺功能在临床和生化方面通常正常。桥本脑病似乎是一种罕见疾病，但由于它对皮质类固醇治疗有反应，因此在“检查阴性的脑病”病例中必须予以考虑。首先通过神经影像学检查和脑脊液检查排除其他中毒、代谢和感染性脑病病因来进行诊断。神经影像学检查结果往往无助于明确诊断。排除这些情况后的常见鉴别诊断包括克雅氏病、快速进展性痴呆以及副肿瘤性和非副肿瘤性边缘叶脑炎。在典型临床表现的背景下，抗甲状腺抗体，尤其是抗甲状腺过氧化物酶抗体的高滴度具有诊断意义。然而，这些抗体在健康普通人群中也可能检测到滴度升高。皮质类固醇治疗几乎总是成功的，尽管如果突然停止这种治疗可能会复发。其他形式的免疫调节，如静脉注射免疫球蛋白和血浆置换，也可能有效。尽管与自身免疫性甲状腺疾病有关，但桥本脑病的病因尚不清楚。抗甲状腺抗体可能不具有致病性，但滴度可以作为治疗反应的一个指标。病理检查结果可提示炎症过程，但通常不存在严重血管炎的特征。临床症状、甲状腺疾病、自身抗体模式和脑病理之间的联系有待通过研究进一步阐明。桥本脑病可能会被归入一组非血管炎性自身免疫性炎性脑膜脑病中。这一组可能包括与电压门控钾通道抗体相关的边缘叶脑炎等疾病。一些作者建议舍弃与桥本的任何关联，将该病重新命名为“与自身免疫性甲状腺炎相关的类固醇反应性脑病”，以更好地反映目前对这种疾病的有限认识。
